Known in the art is a process for producing phosphorus from flue gases containing vapours of phosphorus, carbon monoxide, gaseous compounds of fluorine and silicon, fine dust, by treating thereof at a temperature of from 130.degree. to 350.degree. C. with steam supplied in an amount of 10 to 100 g per m.sup.3 of the gas, followed by condensation of the gases with water to recover phosphorus and produce a slime. The slime into which there passes up to 12% of phosphorus, as calculated for the mass of phosphorus produced, is delivered to further processing (SU, A, No. 1017670.)
This prior art process is noted for a considerable slime formation, but the recovery of phosphorus from such slimes is hindered due to the presence of asphalt-resin stabilizers therein.
Also known is a process for producing phosphorus, comprising melting of a phosphorite ore (phosphate rock) in the presence of a reducing agent (coke) and quartzite with the formation of flue gases containing vapours of phosphorus, outdusting thereof in electric filters and condensation with water to recover phosphorus and a slime. The latter is delivered to reprocessing to obtain phosphorus (SU, A, No. 981211). The flue gases prior to the condensation are treated with vapours or an emulsion of an organosilicon liquid such as polymethylsiloxane.
In carrying out this process 10% of phosphorus by mass of the produced phosphorus passes into the slime which has an increased content of asphalt-resin substances.
Furthermore, the employed organosilicon liquids are hardly available and hazardous, so that commercial implementation of the process becomes rather difficult.
From the slimes obtained in the above-described processes it is difficult to recover phosphorus due to a considerable stabilization of phosphorus particles therein by asphalt-resin substances. They are usually subjected to an extraction with organic agents such as carbon tetrachloride in the presence of various oxidizing agents (SU, A, No. 856976). The degree of recovery of phosphorus from such slimes is not more than 70%. Furthermore, the extraction is carried out at a mass ratio of the extraction agent to the slime of 8-10:1, so that the process in general is complicated. Hydrolysis of the extraction agent results in the formation of hydrochloric acid which has a detrimental effect on the corrosion-resistance of the equipment.